2008 S80 T6 code P0171, PCV issue?

Post by **VCA** » 17 Jan 2016, 16:13

Good day MVS!

I've got an '08 S80 T6 with its first 'I'm stumped' problem. I'm getting an ECM-P017100 (system too lean). It's too lean in bin 1,1 (idle basically), with the long term fuel trim going to 1.30 in that bin, but with all others being right around 1. No obvious vacuum leaks. However, I noticed vacuum at the dipstick that makes a sucking sound when pulling the dipstick. I see the Volvo test shows that crankcase vacuum should be between -0.2 and -0.5 kPa. I'm getting -2 in Hg of vacuum (-6.7kPa) at the dipstick. I also notice an oil 'scunge' in the vicinity of the oil separator's pipe that goes to the intake pipe that feeds the turbo. Does this mean what I think it means (failed oil separator)?

Any other things I need to look at on this car? I've checked all the obvious piping with no results.

Thank you!

Post by **VCA** » 18 Jan 2016, 18:48

OK, so the oil trap was bad for sure. There was a vacuum leak at the little hole that the membrane uses for its pressure reference. New oil trap installed today and no more leak there, as well as significantly less crankcase vacuum...there's definitely a vacuum, but it's not 2 in Hg of vacuum, it barely tips my vacuum gauge into the vacuum range now (0.5 kPa vacuum is about 0.14 in Hg)...perfect. However, after resetting adaptives and test driving, the adaptives for area 1,1 are at 1.11 and I suspect climbing...so I still have an air leak somewhere. *&%$#@! Help?

Post by **VCA** » 19 Jan 2016, 20:21

OK, so I just wasn't patient enough: the long term fuel trim went up to 1.14 after a long drive today and later came down to 1.12 after a drive. All's well.

Lesson learned: high vacuum at the dipstick might be just as obvious a sign of PCV failure as no vacuum at all...at least on P3 cars.

Jabber5 · Post by **Jabber5** » 09 May 2018, 08:57

I have the same year, same model, same engine, same code. How did you figure out that the leak was coming from the oil trap?

Post by **ndphotonl** » 25 Sep 2018, 08:58

1.14% LTFT is awesome, good job.

Post by **pierremcalpine** » 26 Sep 2018, 05:24

VCA wrote: ↑19 Jan 2016, 20:21 OK, so I just wasn't patient enough: the long term fuel trim went up to 1.14 after a long drive today and later came down to 1.12 after a drive. All's well.

Lesson learned: high vacuum at the dipstick might be just as obvious a sign of PCV failure as no vacuum at all...at least on P3 cars.

Thank you for sharing! Very helpful.